So I'm the poor sap who decided to take on building a Java backend for Bespin. Michael Mahemoff wonders if Bespin will ever have multiple backends, and I obviously believe the answer is yes, so I thought I'd go into why I think it is a good idea.
Bespin represents an opportunity to fundamentally change how we develop software. It dramatically lowers the barrier of entry to development, ideal for software modules that are smaller, more focused, and testable. At this point, it isn't suited to all software development, but for extension systems like a good plugin system that allows small bits of code to be plugged into a system at runtime, I think it is a perfect fit.
While Java development, for example, can be quite fast once you get all your frameworks, build systems, and IDE's in place, it also be a house of cards that the slightest network or external server-related wind can bring to a tumbling crash. I'd rather have an application focus on providing a solid platform with accessible API's, then provide a development environment in the app itself to write little plugins. Then, any developer can log in and get to writing real code without all the setup and build issues.
Therefore, building an embeddable Java backend is critical since all the web applications that I work on are Java-based. There are many times I want to write a little plugin, but dealing with Maven 2 and IDEA seems overkill. Being able to log into a dev server and hack away would dramatically reduce the time from idea to code and make it more likely I'll actually do it and not put it on the "I should do that someday" shelf.
They say in order to take advantage of your creative potential, you should carry around a notepad to jot down ideas as you have them. Think of Bespin as a code-able notepad.